HAZMAT CDL Practice Test

When should liquid discharge valves on a compressed gas tank be kept closed?

1. When preparing for transport

2. Only when loading

3. Except when loading and unloading

4. When the pressure is low

The correct answer is: Except when loading and unloading

Liquid discharge valves on a compressed gas tank should be kept closed except when loading and unloading. This is crucial for ensuring the safe transport of hazardous materials. Keeping these valves closed helps prevent accidental release of the gas, which can lead to serious safety hazards, including fire, explosion, or environmental contamination. Only opening the valves during loading and unloading allows for controlled management of the substance being transferred, ensuring that it is done safely and in accordance with regulations. This practice minimizes the risk of leaks and potential exposure to dangerous materials during transport. Maintaining the valves in a closed position at all other times is part of standard safety protocols and practices that all drivers and handlers of hazardous materials must follow to protect themselves, others, and the environment.